1989 3cyl 75 HP Evinrude - Running on One Cylinder? (Videos Included)

[OnThePontoon89]

Symptoms are as follows

• Idles fine at 800 RPMs however when put in gear the engine bogs out. To get it to not bog under light load I have to set the idle very high. The motor will then idle at 700-800 RPM in the tank but scream on muffs. If I do not adjust the idle very high it will run fine on muffs. This condition only presents in the water or tank.
  
  
• At WOT the engine is non responsive. It will very slowly climb to about 18 MPH.

During diagnostics I found the following. I'm unsure if this is right but I will be referring to the top cylinder as cylinder one, middle as cylinder two, bottom as cylinder three.

• Compression is fine. 110 - 120 PSI.
• All cylinders appear to "spit" fuel however cylinder one seems to do it the worst
• When covering cylinder one or three with a plastic bag there is little if any change. When covering cylinder two the engine immediately dies.
• When removing the spark plugs from cylinder one or three the motor runs the exact same. When removing from cylinder two the engine immediately dies.
• I put a spark plug tester inline with all three cylinders. I have spark. I shocked myself on cylinder three so I know for a fact I have spark.
• Pulled the plug on cylinder three and ran the motor. I really don't smell gas nor do I see gas\oil shooting out the hole. This is idle.
• The test tank is very oily after about ten minutes of runtime.
• Not sure if this is an issue but if you watch the last video at the 4 second mark you will notice water pouring out between the mid section and tail section. Otherwise it pisses fine.
• Some mechanic did supposedly rebuild the carbs. Before the carb rebuild I would completely die at WOT and could only idle. I did not run the boat for two years after the rebuild.

I appear to be running on one cylinder, what could be going on here. I'm thinking of moving the cabs around to see if the issue "follows" the carb.

Videos

- Boat-CarbGas - This video shows gas spitting out the carbs.

- Boat-CarbBag - This video shows me covering all carbs with a bag. Only covering the middle kills the engine.

- Boat-PullPlug - This video shows me pulling all plugs on the motor and observe no change. Pulling the middle kills the engine.

- Boat-2Plugs - This video shows the motor running with cylinder one and cylinder three's plug wires removed.

 

[flyingscott]

The fact you can hold those 2 spark plug wires means you do not have spark on those 2. . Is there water intrusion? those motors are known for exhaust gasket leaks. Timer base connected and moving ? Get an open air spark checker. make sure spark jumps 7/16 "

 

[OnThePontoon89]

The fact you can hold those 2 spark plug wires means you do not have spark on those 2. . Is there water intrusion? those motors are known for exhaust gasket leaks. Timer base connected and moving ? Get an open air spark checker. make sure spark jumps 7/16 "

I do have spark on those two, I just carefully grabbed them at the end of the boot and pulled it back which is why I didn't get shocked.

• I purchased a spark tester from autozone and put it inline. All 3 cylinders you can see a light.
  
  
• I personally got a healthy shock from the bottom one. You can also see the spark arc, it's just not evident in the video.

Timer base is connected and moves.

What would be the best way to check for water intrusion? I did take the number three plug off and no water shot out.

 

[OnThePontoon89]

I think my reeds are shot.

So here's where I am guys.... Cleaned and dipped the top and bottom carb. Not sure if it's due to increased idle but the top cylinder *can* hold it's own (still not as good as the middle). Bottom will not hold it's own. When I say hold it's own I mean run only on one cylinder. I am still getting the spitting so I removed the manifold to expose the reeds. These seem to look bad. The middle obviously looks best but there is still a little hole. Will you ever get these to seal 100% perfect so there's no light at all? Here's some videos

I'm going to replace. Any advice on the part number for JUST the reeds and not the whole assembly. I found some on ebay not sure how good the carbon fiber ones or I should stick w\ OEM. are Reed Valves 1982 Evinrude for sale | eBay https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4432023.m570.l1313&_nkw=reed+valves+1982+evinrude&_sacat=0

 

[cyclops222]

I was told the Reeds ONLY affected very low speeds. Unless they are stuck closed somehow.

 

[tphoyt]

If worth checking for spark with an open air gap.
The light will confirm spark but doesn’t tell you how strong it is.
Jmo

 

[OnThePontoon89]

If worth checking for spark with an open air gap.
The light will confirm spark but doesn’t tell you how strong it is.
Jmo

I did perform resistance tests and all coil packs look good. I purchased the components needed to make a DVA so I can do peak voltage tests. Once I get my reeds I’ll put it back together and do an air gap test. I assume just take the plug out, ground it, and see if it sparks.

I was told the Reeds ONLY affected very low speeds. Unless they are stuck closed somehow.

That is one of my issues. The bot can not hold its own under load unless I set the idle insanely high. Then it screams like a daemon on muffs only to be 1000 at loaded idle. Anything lower stalls. I also have clear fuel spitting, that can’t be good for the mixture.

Im not an expert but there’s a clear issue so I’m replacing them. At least I’m starting from a solid baseline.

 

[racerone]

Reed valves work at all RPM !!!!---Reeds do NOT stick closed.------That motor does not look like an 89 model to me.-----So post the model # here.-----It looks like a 49 cube model .----Compression is a lot higher on those.

 

[OnThePontoon89]

Reed valves work at all RPM !!!!---Reeds do NOT stick closed.------That motor does not look like an 89 model to me.-----So post the model # here.-----It looks like a 49 cube model .----Compression is a lot higher on those.

Youre correct it is a 1982. I forgot to update this.

I’m not implying they stick closed. I’m implying that they are stuck open and the top cylinder is the worst. You can see in the videos the light shinnng through.

I just don’t know how “bad” that’s considered and I’d that amount of spacing will cause issues. Rom my reading any light shining through is bad.

 

[racerone]

Well---Some will argue , but 110 PSI compression is BAD on one of those motors!---So you have a bad gauge or a motor that needs major work.----Remove cylinder head.----Just 22 bolts and easy.----Head gasket is cheap if it is bad !-----But I do not believe you will like what you see here.----Impeller replace in water pump ?----Overheat horn tested lately?

 

[OnThePontoon89]

The man

Well---Some will argue , but 110 PSI compression is BAD on one of those motors!---So you have a bad gauge or a motor that needs major work.----Remove cylinder head.----Just 22 bolts and easy.----Head gasket is cheap if it is bad !-----But I do not believe you will like what you see here.----Impeller replace in water pump ?----Overheat horn tested lately?

The manual states 100 psi is min spec

 

[racerone]

What manual ??----Good luck with your motor.----I bought 21 of these motors at auction one time.----At 110 PSI the motor comes apart for major work !

 

[OnThePontoon89]

What manual ??----Good luck with your motor.----I bought 21 of these motors at auction one time.----At 110 PSI the motor comes apart for major work !

Interesting. The motor is a E70ELCNB. 1982 3 cyl. What do you see compression typically at?

It’s a shop manual I got from a forum. It seems pretty accurate. The cover is red and grey and says “Evinrude Johnson Outboard Shop Manual”

 

[racerone]

Should be around 140 PSI

 

[OnThePontoon89]

Should be around 140 PSI

Thanks. Typically is low compression on these the result of a head gasket or piston/rings/hone

Some people report lower .

Evinrude 70hp ideal compression?

I just bought a boat with an Evinrude 70 3cyl (1996) non vro . I picked it up pretty cheap because I was expecting to do some engine work. I started it up on the muffs and it seemed to by idling high (throttle tabs in carb were shut as far as they go) but running never the less. So I decided to...

forums.iboats.com

 

[racerone]

Good luck with this motor.----Maybe invest a few hundred beer tokens in new reed valves and test run.

 

[OnThePontoon89]

Good luck with this motor.----Maybe invest a few hundred beer tokens in new reed valves and test run.

Thanks. I’m going to start with reeds. Got them for $50 on Amazon

 

[saltchuckmatt]

How much compression did these motors have when new?

 

[OnThePontoon89]

How much compression did these motors have when new?

Unsure. It’s an 80s motor and I got the boat used